Finding the right tests…
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Finding the right tests…
X-Ray
A KUB X-ray is a plain film of your abdomen focused on your kidneys, ureters, and bladder — the parts of your body that make and carry urine. You lie down on your back for this scan, and a single image captures the area from around your lower ribs down to your pelvis. Doctors order it most often when they suspect a kidney or bladder stone, to see if a stone is present and roughly where it sits. It's a quick first look, not the final word — some stones, especially smaller ones or certain chemical types, don't show up clearly on a plain X-ray and need an ultrasound or CT scan to confirm.
This scan covers your kidneys, ureters, and bladder in one lying-down image. Doctors use it to look for kidney or bladder stones and to get a general view of the bowel gas pattern in your abdomen.
KUB stands for kidneys, ureters, and bladder, the three urinary structures this X-ray is aimed at. You lie flat on your back while a single image is taken covering your abdomen from around your lower ribs down to your pubic bone.
A KUB X-ray is a reasonable first step for a suspected kidney stone because many stones contain enough calcium to show up as a bright spot on the film. But not every stone is visible this way — stones made mostly of uric acid, for instance, can be essentially transparent on a plain X-ray, and overlying bowel gas can hide the kidneys themselves. If your doctor still suspects a stone after a normal KUB, they'll usually order an ultrasound or CT scan next.
A KUB is taken lying down and is read mainly for stones and general bowel gas pattern. An erect, or standing, abdomen X-ray is a different, purpose-built view — used to look for free air or fluid levels that only show up when you're upright, pointing to a perforation or blockage rather than a stone.
Not always. Many stones contain enough calcium to appear on a plain X-ray, but some types, such as uric acid stones, often don't show up clearly. Your doctor may follow up with an ultrasound or CT scan if a stone is still suspected.
A KUB is a quick X-ray that shows many but not all stones. An ultrasound and CT scan pick up a wider range of stones, including ones that don't show on a plain X-ray, which is why your doctor may order one after a normal KUB.
Yes, a KUB X-ray is taken with you lying on your back, unlike an erect abdomen X-ray which is taken standing up.
No. A KUB is a lying-down view focused on the urinary tract and stones. An abdomen erect X-ray is a standing view used to check for free air or fluid levels linked to a perforation or blockage.
This page is general information about the test, not medical advice. Your own report's reference ranges apply — please discuss your results with your doctor.
Tell your doctor and the centre if you're pregnant or think you might be. This scan involves the abdomen directly, so your doctor will weigh whether it's needed and consider other options like ultrasound first.
A KUB gives a general view of the bladder outline and can pick up some bladder stones, but it isn't a detailed bladder test. Your doctor may add other scans if a bladder-specific concern needs closer evaluation.
A CT scan detects stones that don't show up on a plain X-ray and gives more detail on size, location, and whether a stone is blocking urine flow. Doctors often move to CT when a KUB doesn't answer the question.